These plots are generated from the imaging data obtained by these
cameras during the night. Three panels are provided: the measured
image quality from the raw images, the image quality converted to a
reference filter (R) assuming the scaling of
Λ1/5; and the image quality in R corrected to
zenith assuming the scaling airmass3/5.

Select the 'tonight' or
'recent' buttons to see
a plot of the seeing for the current night or past three hours. These
plots begin at 18:00 HST and stop at 06:00 HST. If the CFHT dome is
closed or the clouds are too thick, the plots will be marked 'no data
available'. These plots will update automatically every few minutes.
Since not all cameras are supported, please note the date of the
plot. When an unsupported camera is mounted, the displayed plots may
be out of date.

Notes for specific cameras

CFH12K The seeing measurements are derived from chip 03 only, which
is located near the center of the mosaic and is the least succeptible
to optical distortion in the wide-field corrector. Sextractor is used
to extract stellar measurements, and these are filtered to select the
true stars, excluding the galaxies, from the data.

CFHT-IR The seeing measurements are based on the entire
chip. Sextractor is used to extract stellar measurements, and these
are filtered to select the true stars, excluding the galaxies, from
the data. The recipe for this analysis has not yet been well
tested. Use these numbers with some caution. Given the small
field-of-view of CFHT_IR compared with CFH12K, and the lower density
of stars, these seeing measurements are likely to be more subject to
error than those from CFH12K.